Plasma repositories sprint cleaning

[Nicolas Fella]

Hi,

while porting Plasma repos to Qt6 I've come across several repos in the
plasma/ namespace on invent that I found questionable:

- khotkeys: consensus seems to be to abandon it, because maintaining two
global shortcut systems is no joy: https://phabricator.kde.org/T2050.
It's still released with 5.27 though

- ksysguard: We stopped releasing/maintaining it several releases ago.
Not part of any supported release. Could be archived?

- kwrited: The functionality is kind of old/niche. Is it worth having at
all? If yes, given it is quite tiny, would it make sense to fold it into
plasma-desktop instead of having it separate?

- kwayland-server: Obsolete implementation detail. Not released any
more. Can probably be archived now

- lancelot: An alternative Plasma launcher. No releases, not much
activity in recent years. If anyone cares about it it might be better of
maintained outside of KDE to avoid impression that it is "officially"
supported

- plasma-active-window-control: No release, a little activity in recent
times. What do we do with it?

- plasma-redshift-control: No releases. Does this provide anything
interesting compared to the "official" night color stuff?

- plasma-simplemenu: Had releases in the past, but last one is from 4
years ago. Semi-active recently. Might be worth incorporating into
proper Plasma release?

- plasma-tests: Is this useful at all?

- smaragd: Last release 5 years ago. Not a whole lot of activity since
then. Make it part of the proper Plasma release or kill it?


I'm asking this mainly to see what "needs" to be ported to Qt6/Plasma6,
but I also think it's important to have a clear messaging about what we
as a "Plasma Team" properly support and what is on a best-effort basis
by whoever feels like supporting it.

Cheers

Nico